The Shape of Code

What does it mean for somebody to claim to know a computer language? In the commercial world it means the person is claiming to be capable of fluently (i.e., only using knowledge contained in their head and without having to unduly ponder) reading, and writing code in some generally accepted style applicable to that language. The academic world generally sets a much lower standard of competence (perhaps because most of its inhabitants leave before any significant expertise is acquired). If I had a penny for every recent graduate who claimed to know a language and was incapable of writing a program that read in a list of integers and printed their sum (I know companies that set tougher problems but they do not seem to have higher failure rates), I would be a rich man.

One experiment asked 21 postgraduate and academic staff which of the following individuals they would regard as knowing Java:

The results were:

_ NO YES
A 21  0
B 18  3
C 16  5
D  8 13
E  0 21

These answers reflect the environment from which the subjects were drawn. When I wrote compilers for a living I did not consider that anybody knew a language unless they had written a compiler for it, a point of view echoed by other compiler writers I knew.

I’m not sure that commercial developers would be happy with answer (E), in fact they could probably expand (E) into five separate questions that tested the degree to which a person was able to combine various elements of the language to create a meaningful whole. In the commercial world stage (E) is where people are expected to start.

The criteria used to decide whether somebody knows a language depends on which group of people you talk to; academics, professional developers and compiler writers each have their own in-group standards. In a sense the question is irrelevant, a small amount of language knowledge applied well can be used to do a reasonable job of creating a program for most applications.